The Pathology/Microbiology Core provides a centralized service for all projects so that animal and bacterial elements of program experiments are standardized and high quality. The core generates quality-controlled medium for growth of B. burgdorferi; B. burgdorferi isolates for use in laboratory animals; culture of B. burgdorferi from animal tissues; technical services for standardized inoculation, immunization and tissue collection; coordination of animal experiments utilizing core services; and professional pathology services for evaluation of tissues from experimental animals.